Immunity over inability: The spontaneous regression of cancer

Hypothesis: hematogenous metastatic cancer cells of solid tumors may disguise themselves as memory macrophages for metastasis

German pathologist Otto Aichel suggested, a century ago, that the cancer cell acquired its metastatic property from a leukocyte via cell-cell fusion. Since then, several revised versions of this theory have been proposed. Most of the proposals attribute the generation of the metastatic cancer cell to the fusion between a primary cancer cell and a macrophage. However, these theories have not addressed several issues, such as dormancy and stem cell-like self-renewal, of the metastatic cancer cell. On the other hand, recent studies have found that, like T- and B-/plasma cells, macrophages can also be categorized into naïve, effector, and memory/trained macrophages. As a memory/trained macrophage can enter dormancy/quiescence, be awakened from the dormancy/quiescence by acquainted primers, and re-populate via stem cell-like self-renewal, we, therefore, further specify that the macrophage fusing with the cancer cell and contributing to metastasis, belongs with the memory/trained macrophage, not other subtypes of macrophages. The current theory can explain many puzzling clinical features of cancer, including the paradoxal effects (recurrence vs. regression) of microbes on tumors, "spontaneous" and Coley's toxin-induced tumor regression, anticancer activities of β-blockers and anti-inflammatory/anti-immune/antibiotic drugs, oncotaxis, surgery- and trauma-promoted metastasis, and impact of microbiota on tumors. Potential therapeutic strategies, such as Coley's toxin-like preparations, are proposed. This is the last article of our trilogy on carcinogenesis theories.

Inter-cell type interactions that control JNK signaling in the Drosophila intestine

JNK signaling is a critical regulator of inflammation and regeneration, but how it is controlled in specific tissue contexts remains unclear. Here we show that, in the Drosophila intestine, the TNF-type ligand, Eiger (Egr), is expressed exclusively by intestinal stem cells (ISCs) and enteroblasts (EBs), where it is induced by stress and during aging. Egr preferentially activates JNK signaling in a paracrine fashion in differentiated enterocytes (ECs) via its receptor, Grindelwald (Grnd). N-glycosylation genes (Alg3, Alg9) restrain this activation, and stress-induced downregulation of Alg3 and Alg9 correlates with JNK activation, suggesting a regulatory switch. JNK activity in ECs induces expression of the intermembrane protease Rhomboid (Rho), driving secretion of EGFR ligands Keren (Krn) and Spitz (Spi), which in turn activate EGFR signaling in progenitor cells (ISCs and EBs) to stimulate their growth and division, as well as to produce more Egr. This study uncovers an N-glycosylation-controlled, paracrine JNK-EGFR-JNK feedforward loop that sustains ISC proliferation during stress-induced gut regeneration.

Complex associations between cancer progression and immune gene expression reveals early influence of transmissible cancer on Tasmanian devils

The world's largest extant carnivorous marsupial, the Tasmanian devil, is challenged by Devil Facial Tumor Disease (DFTD), a fatal, clonally transmitted cancer. In two decades, DFTD has spread across 95% of the species distributional range. A previous study has shown that factors such as season, geographic location, and infection with DFTD can impact the expression of immune genes in Tasmanian devils. To date, no study has investigated within-individual immune gene expression changes prior to and throughout the course of DFTD infection. To explore possible changes in immune response, we investigated four locations across Tasmania that differed in DFTD exposure history, ranging between 2 and >30 years. Our study demonstrated considerable complexity in the immune responses to DFTD. The same factors (sex, age, season, location and DFTD infection) affected immune gene expression both across and within devils, although seasonal and location specific variations were diminished in DFTD affected devils. We also found that expression of both adaptive and innate immune genes starts to alter early in DFTD infection and continues to change as DFTD progresses. A novel finding was that the lower expression of immune genes MHC-II, NKG2D and CD8 may predict susceptibility to earlier DFTD infection. A case study of a single devil with regressed tumor showed opposite/contrasting immune gene expression patterns compared to the general trends observed across devils with DFTD infection. Our study highlights the complexity of DFTD's interactions with the host immune system and the need for long-term studies to fully understand how DFTD alters the evolutionary trajectory of devil immunity.

A dual-functional oncolytic adenovirus ZD55-aPD-L1 scFv armed with PD-L1 inhibitor potentiates its antitumor activity

BACKGROUND

Clinical data indicate that a substantial portion of cancer patients, though eligible for immune checkpoint inhibitor (ICI) therapy, cannot fully benefit from ICI monotherapy due to the poor immunogenicity of tumors and lack of tumor-infiltrating lymphocytes within the 'cold' tumor microenvironment (TME). In addition to poor antibody penetrance into the TME, systemic delivery of ICIs is associated with immune-related adverse events (irAEs) among recipients, some of which are life-threatening. Oncolytic virotherapy is a potentially viable approach to improving the efficacy of ICI therapy because of their ability to selectively replicate and lyse tumor cells, release tumor-associated antigens (TAAs), induce inflammatory response and promote lymphocyte infiltration in tumors.

METHODS

A recombinant oncolytic adenoviruses (OAd), denoted ZD55-aPD-L1 scFv, which carried the expression cassette for anti-PD-L1 scFv was constructed by molecular cloning. Western blot and ELISA assay were performed to detect aPD-L1 scFv expression. Flow cytometry were used to analyse PD-L1 expression and count tumor cells. Co-culture assay of human peripheral blood mononuclear cells (PBMCs) with tumor cells in vitro and triple-negative breast cancer (TNBC) MDA-MB-231 tumor-bearing model in vivo were evaluated the antitumor effects of recombinant oncolytic adenoviruses ZD55-aPD-L1 scFv.

RESULTS

We found that cells infected with recombinant oncolytic adenovirus ZD55-aPD-L1 scFv can effectively express aPD-L1 scFv, which function similarly to its full-length anti-PD-L1 antibody. PBMCs have inherently very limited killing effect on tumor cells even with administration of anti-PD-L1 antibody as observed from our in vitro co-cultures. Treatment consisting of ZD55 alone or ZD55 combined with anti-PD-L1 antibody yielded mediocre antitumor efficacy in subsequent in vitro and in vivo investigations, but were all substantially surpassed by the synergistic antitumor effects observed with ZD55-aPD-L1 scFv treatment. We show that the concomitant direct oncolysis by the recombinant OAd and localized autocrine/paracrine interception of PD-1:PD-L1 checkpoint interaction mediated by ZD55-aPD-L1 scFv-infected cells is exceedingly superior to co-administration of ZD55 and anti-PD-L1 antibody in the human TNBC mice model.

CONCLUSIONS

Our results provided evidence for the development of novel strategies, in this case an anti-PD-L1 scFv-armed OAd, to bolster immune responses to 'cold' tumors and to improve therapeutic responsiveness to ICIs.

Spontaneous Regression of Primary Cutaneous Diffuse Large B-Cell Lymphoma on Sequential FDG PET

ABSTRACT

Primary cutaneous diffuse large B-cell lymphoma, leg type is a rare, aggressive lymphoma characterized by skin involvement predominantly in the lower extremities. We present a case of an elderly woman with pathology diagnosis of primary cutaneous diffuse large B-cell lymphoma, leg type with spontaneous regression without systematic therapy documented by sequential FDG PET scans and clinical follow-up.

Complete Regression of Endobronchial Carcinoid Tumor after an Endoscopic Biopsy

An 80-year-old woman who had been diagnosed with an endobronchial carcinoid tumor visited our hospital for treatment with an endoscopic technique. However, a bronchoscopic examination at our hospital showed spontaneous regression of the tumor at the orifice of the right middle lobar bronchus. Chest computed tomography five months later revealed no local recurrence. This is the second report of an endobronchial carcinoid tumor vanishing after an endoscopic biopsy.

Impact of Sepsis on the Oncologic Outcomes of Advanced Epithelial Ovarian Cancer Patients: A Multicenter Observational Study

OBJECTIVE

The sepsis-induced inflammatory response may potentially affect malignant cells. Recently, a case of spontaneous regression of a histologically confirmed International Federation of Gynecology and Obstetrics (FIGO) stage IIIC epithelial ovarian cancer (EOC) following sepsis was reported. The aim of our study was to assess the impact of sepsis on the oncologic outcomes of advanced-stage EOC patients.

METHODS

Gynecologic oncologic patients admitted to the Intensive Care Unit of three oncologic centers between 2006 and 2019 were identified and patients who experienced sepsis following advanced-stage EOC diagnosis were selected. Survival outcomes were compared with advanced-stage EOC patients from the Netherlands Cancer Registry (NCR). To correct for case-mix differences, propensity score matching using 1:3 nearest neighbor matching was conducted after which survival analyses were repeated.

RESULTS

A total of 18 of 215 patients with advanced-stage EOC experienced sepsis. Sepsis patients had similar distributions of patient, tumor, and treatment characteristics to 3988 patients from the NCR cohort. A total of 3 of 18 patients died from the complications of sepsis. While the remaining patients initially responded to treatment, 14/15 patients relapsed. The median (IQR) overall survival was 31 (24-44) and 35 (20-60) months for the sepsis and unmatched NCR cohort (p = 0.56), respectively. The median (IQR) progression-free survival was 16 (11-21) and 16 (11-27) months (p = 0.90), respectively. Survival outcomes did not differ following propensity matching (overall survival of 31 (24-44) vs. 36 (20-56) months, p = 0.40; progression-free survival of 16 (11-21) and 16 (12-21) months, p = 0.72).

CONCLUSION

In this observational study, the occurrence of sepsis did not affect the oncologic and survival outcomes of advanced-stage EOC patients.

Giant-cell-poor giant cell tumor of bone: report of two cases and literature review

Giant cell tumor of bone (GCTB) is a locally aggressive tumor that shows predilection for the metaphysis/epiphysis of long bones, with an incidence of 4-5% of primary bone tumors. GCTB shows two main populations of cells: mononuclear cells and non-neoplastic multi-nucleated giant cells, with or without fibrous background. On the other hand, giant-cell-poor GCTB are rare with only few reports in the literature. These cases offer a diagnostic challenge, given the absence of giant cells and such cases have consistently been shown to harbor the H3F3A gene mutation by sequencing. The H3.3 G34W mutation-specific monoclonal antibody has shown high specificity in the diagnosis of GCTB. Two cases of giant-cell-poor GCTB are presented in this study, in which giant cells were absent or sparse and the diagnosis of GCTB was confirmed by the expression of H3.3 G34W monoclonal antibody in the mononuclear cells by immunohistochemistry. Whether this represents a histologic variant of GCTB or partial involution of GCTB is not yet fully understood; however, an immune response, infectious/inflammatory reaction, and/or anti-tumor cytokine production have been purported to be factors inciting disease regression in GCTB.

Complete Spontaneous Regression of Colorectal Cancer: A Report of Two Cases

Spontaneous regression of cancer is rare, and rarer still in colorectal cancer. We present a report of two cases of spontaneous regression of histologically proven proximal colonic cancers described in detail, alongside endoscopic, histological, and radiological images. We discussed the potential mechanisms by reviewing previous literature.

Adjuvant therapy options in renal cell carcinoma - targeting the metastatic cascade

Localized renal cell carcinoma (RCC) is primarily managed with nephrectomy, which is performed with curative intent. However, disease recurs in ~20% of patients. Treatment with adjuvant therapies is used after surgery with the intention of curing additional patients by disrupting the establishment, maturation or survival of micrometastases, processes collectively referred to as the metastatic cascade. Immune checkpoint inhibitors and vascular endothelial growth factor receptor (VEGFR)-targeting tyrosine kinase inhibitors (TKIs) have shown efficacy in the treatment of metastatic RCC, increasing the interest in the utility of these agents in the adjuvant setting. Pembrolizumab, an inhibitor of the immune checkpoint PD1, is now approved by the FDA and is under review by European regulatory agencies for the adjuvant treatment of patients with localized resected clear cell RCC based on the results of the KEYNOTE-564 trial. However, the optimal use of immunotherapy and VEGFR-targeting TKIs for adjuvant treatment of RCC is not completely understood. These agents disrupt the metastatic cascade at multiple steps, providing biological rationale for further investigating the applications of these therapeutics in the adjuvant setting. Clinical trials to evaluate adjuvant therapeutics in RCC are ongoing, and clinical considerations must guide the practical use of immunotherapy and TKI agents for the adjuvant treatment of localized resected RCC.

Integrating Immunotherapy into Multimodal Treatment of Head and Neck Cancer

Patients with locally advanced head and neck squamous cell carcinoma (HNSCC) have a poor prognosis, with a significant risk of progression or death despite multimodal treatment with surgery, chemotherapy, and radiotherapy. Immune checkpoint inhibitors targeting the programmed death receptor-1 (PD1) have dramatically changed the treatment landscape for recurrent/metastatic disease, improving overall survival in both the first- and second-line palliative settings. This success has driven the investigation of treatment strategies incorporating immunotherapy earlier into the multimodal curative-intent or salvage treatment of both locally advanced and recurrent/metastatic HNSCC. This review encompassed the following three subjects, with a focus on recently reported and ongoing clinical trials: (1) the use of neoadjuvant immunotherapy prior to surgery for locally advanced HNSCC, (2) the use of immunochemoradiotherapy for locally advanced head and neck cancers, and (3) novel uses of immunotherapy in the salvage of recurrent/metastatic HNSCC via a combined modality, including reirradiation paradigms. The results of these studies are eagerly awaited to improve patient outcomes in this challenging disease.

Case report: Spontaneous remission of synchronous endometrial and ovarian cancers following pregnancy

Introduction

Endometrial cancer is one of the most common malignancies affecting women. It is uncommonly diagnosed in young women, particularly in the absence of abnormal vaginal bleeding symptoms.

Case presentation

A 28-year-old woman was referred to our department with lower abdominal pain. Transvaginal ultrasound showed a complex right adnexal mass with mixed echogenicity. Magnetic resonance imaging (MRI) identified a right-sided, torted, cystic solid ovarian mass, and a polypoid lesion in the uterine cavity.

Diagnosis

Following multidisciplinary team advice, hysteroscopic transcervical resection of endometrial polypoid mass and laparoscopic right salpingo-oophorectomy was performed. Histopathologic assessment of the endometrial tissue showed changes consistent with grade 1 endometrioid endometrial carcinoma, while the right ovarian mass showed a well-differentiated endometrioid carcinoma.

Intervention

The patient underwent hormonal treatment and surveillance whilst making a final decision regarding further surgical management. However, the patient stopped hormonal treatment after 2 weeks, went abroad and absconded from treatment for 8 months. On her return, she had conceived naturally and was in the first trimester of pregnancy. Further management was postponed until the patient was 7 weeks postnatal. The patient was not keen on any further surgical management and opted for close surveillance with ultrasound scans and hysteroscopies with endometrial biopsies. All subsequent endometrial biopsies showed normal endometrium, with no evidence of hyperplasia or malignancy.

Outcome

To date, the patient remains on a 6-monthly surveillance plan and is considered to have had complete natural remission of her endometrial and ovarian cancers following pregnancy.

Conclusion

This unique case demonstrates a natural phenomenon, in which the complete, natural remission of endometrial and ovarian cancers occurred following pregnancy and childbirth. The aetiology may be related to the high progesterone levels occurring in pregnancy.

Pathologic complete response following low-dose radiation for advanced oral cavity cancer in a patient with human immunodeficiency virus

BACKGROUND

Advanced squamous cell carcinoma (SCCa) of the oral cavity is often not amenable to curative-intent therapy due to tumor location, tumor size, or comorbidities.

CASE PRESENTATION

A 51-year-old male patient with human immunodeficiency virus and on highly active antiretroviral therapy (HAART) presented with a cT4aN2c SCCa of the tongue. He received a preoperative single course of Quad-Shot radiation therapy to 14 Gy in 4 fractions followed by surgical resection. Patient had no residual carcinoma on surgical pathology and no evidence of disease on subsequent clinical and radiological exams.

CONCLUSIONS

To our knowledge, this is the first case of pathologic complete response for a patient on HAART following a single cycle of the Quad-Shot regimen for advanced oral cavity SCCa. Protease inhibitors in HAART can induce spontaneous tumor regression via inhibition of proteasome function and activation of apoptosis, and thus act as a cancer therapeutic.

Neutrophil-lymphocyte Ratio and C-Reactive Protein Levels are not Associated with Strength, Muscle Mass, and Functional Capacity in Kidney Transplant Patients

Chronic inflammation has been associated with components of sarcopenia; however, these associations are unknown in kidney transplant patients (KTPs). The aim of this study was to associate neutrophil-lymphocyte ratio (NLR) and C-reactive protein (CRP) with strength, muscle mass, and functional capacity in KTPs. A cross-sectional study evaluating 108 KTPs was performed. Strength was evaluated by handgrip strength and five-times-sit-to-stand test (5STS), and appendicular skeletal muscle mass (ASM) was estimated by bioelectrical impedance analysis. The ASM index (ASMI) was calculated using the ASM (kg)/height (m²). Functional capacity was assessed by the 4-m gait speed test and short physical performance battery (SPPB). The electrochemiluminescence method was used for analyzing CRP levels, and the cytometric method XN-3000 Sysmex was used for obtaining leukogram values to calculate the NLR. Linear regression analysis was used to assess the association between systemic inflammation and sarcopenia components, adjusting for confounders. NLR and CRP levels were not associated with handgrip strength (β =  - 0.231, p = 0.389; β =  - 0.291, p = 0.577), 5STS (β =  - 0.114, p = 0.288; β =  - 0.202, p = 0.334), ASM (β =  - 0.027, p = 0.813; β = 0.062, p = 0.788), ASMI (β =  - 0.036, p = 0.242; β = 0.040, p = 0.505), 4-m gait speed (β = 0.013, p = 0.082; β = 0.004, p = 0.769), and SPPB (β = 0.076, p = 0.170; β = 0.152, p = 0.157), respectively. In conclusion, NLR and CRP levels were not associated with muscle mass, strength, and functional capacity in KTPs.

Targeting the gut and tumor microbiota in cancer

Microorganisms within the gut and other niches may contribute to carcinogenesis, as well as shaping cancer immunosurveillance and response to immunotherapy. Our understanding of the complex relationship between different host-intrinsic microorganisms, as well as the multifaceted mechanisms by which they influence health and disease, has grown tremendously-hastening development of novel therapeutic strategies that target the microbiota to improve treatment outcomes in cancer. Accordingly, the evaluation of a patient's microbial composition and function and its subsequent targeted modulation represent key elements of future multidisciplinary and precision-medicine approaches. In this Review, we outline the current state of research toward harnessing the microbiome to better prevent and treat cancer.

Local immune checkpoint blockade therapy by an adenovirus encoding a novel PD-L1 inhibitory peptide inhibits the growth of colon carcinoma in immunocompetent mice

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A novel inhibitory peptide interfering with the PD-L1/PD-1 immune checkpoint pathway, dubbed PD-L1ip3, was designed.

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The affinity of PD-L1ip3 for PD-L1 was only a few times weaker than that of its natural ligand, PD-1.

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Direct treatment with PD-L1ip3 enhanced the ability of CD8⁺ T cells primed with cancer antigens to kill cancer cells in culture.

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A combination treatment including transduction into cancer cells of a gene encoding PD-L1ip3 coupled with direct administration of PD-L1ip3 in peptide form significantly attenuated the growth of murine colon carcinoma in mice.

A novel peptide that interferes with the PD-1/PD-L1 immune checkpoint pathway, termed PD-L1 inhibitory peptide 3 (PD-L1ip3), was computationally designed, experimentally validated for its specific binding to PD-L1, and evaluated for its antitumor effects in cell culture and in a mouse colon carcinoma syngeneic murine model. In several cell culture studies, direct treatment with PD-L1ip3, but not a similar peptide with a scrambled sequence, substantially increased death of CT26 colon carcinoma cells when co-cultured with murine CD8⁺ T cells primed by CT26 cell antigens. In a syngeneic mouse tumor model, the growth of CT26 tumor cells transduced with the PD-L1ip3 gene by an adenovirus vector was significantly slower than that of un-transduced CT26 cells in immunocompetent mice. This tumor growth attenuation was further enhanced by the coadministration of the peptide form of PD-L1ip3 (10 mg/kg/day). The current study suggests that this peptide can stimulate host antitumor immunity via blockade of the PD-1/PD-L1 pathway, thereby increasing CD8⁺ T cell-induced death of colon carcinoma cells. The tumor site-specific inhibition of PD-L1 by an adenovirus carrying the PD-L1ip3 gene, together with direct peptide treatment, may be used as a local immune checkpoint blockade therapy to inhibit colon carcinoma growth.

Delayed Spontaneous Regression of Metastatic Gastric Cancer: A Case Report of a Rare Finding

We discuss the case of a 74-year-old male who was referred with episodes of vomiting, nausea, and weight loss. Ultrasound abdomen had suggested multiple liver metastases and a triple-phase CT scan of abdomen-pelvis confirmed the same. His oesophago-gastro-duodenoscopy (OGD), also known as upper endoscopy (EGD), showed a large ulcerated lesion at the lesser curvature, which was later confirmed to be poorly differentiated adenocarcinoma on biopsy. The patient was started on palliative chemotherapy, which he tolerated poorly, but a CT scan had suggested a minimal reduction in the size of liver metastasis. He was given two cycles of chemotherapy; however, due to poor tolerance and unresponsiveness to chemotherapy, he was referred to palliative care. 

The patient declined any medical support for the next six years, after which he visited his general practitioner (GP) for a follow-up review. Routine blood tests showed new-onset mild iron deficiency anaemia. He denied any symptoms. He was referred to Gastroenterology for repeat OGD, and it showed a tiny nodular area in the stomach at the site of previous cancer, which was reported as non-specific chronic inflammation on biopsy, and CT abdomen showed a marked reduction in size and number of liver metastases. On further clinical review, he reported feeling well and his anaemia resolved without any intervention.

Spontaneous Regression of Metastatic Lesions of Adenocarcinoma of the Gastro-Esophageal Junction

Spontaneous regression of cancer is a rarely recognized entity in modern medicine. Historically, this was recognized and hypothesized that an infection causes immune activation, indirectly stimulating the body to destroy tumor cells. Similarly, immune-oncology has now become a major modality in the treatment of solid and some liquid malignancies. However, now with improved therapeutic modalities in the oncology world, one does not get to appreciate our own immune system’s ability to fight cancer. We present a patient who had spontaneous regression of metastatic adenocarcinoma of the gastroesophageal junction (GEJ). The patient is a 58-year-old female who had presented with early satiety and dysphagia for which she underwent esophagogastroduodenoscopy which showed an esophageal mass and endoscopic ultrasounds (EUSs) confirmed adenocarcinoma of the GEJ with metastasis to the regional lymph nodes and left supraclavicular lymph nodes. The patient had refused to undergo any surgical, medical oncological, or holistic treatments. Interim disease monitoring positron emission tomography-computed tomography (PET-CT) showed resolution of the metastatic sites of gastroesophageal cancer with clinical improvement of her symptoms. She continues to have this distant regression of metastatic gastroesophageal cancer six months after the initial diagnosis. In literature, spontaneous cancer regression has been reported in melanoma, renal cell carcinoma, and basal cell carcinoma. To our knowledge, this is the first case reported of spontaneous regression of metastatic lesions involving adenocarcinoma of the GEJ with no medical or surgical intervention. 

Resolution of inflammation: An organizing principle in biology and medicine

The resolution of inflammation has emerged as a critical endogenous process that protects host tissues from prolonged or excessive inflammation that can become chronic. Failure of the resolution of inflammation is a key pathological mechanism that drives the progression of numerous inflammation-driven diseases. Essential polyunsaturated fatty acid (PUFA)-derived autacoid mediators termed 'specialized pro-resolving mediators' (SPMs) regulate endogenous resolution programs by limiting further neutrophil tissue infiltration and stimulating local immune cell (e.g., macrophage)-mediated clearance of apoptotic polymorphonuclear neutrophils, cellular debris, and microbes, as well as counter-regulating eicosanoid/cytokine production. The SPM superfamily encompasses lipoxins, resolvins, protectins, and maresins. Our understanding of the resolution phase of acute inflammation has grown exponentially in the past three decades with the discovery of novel pro-resolving lipid mediators, their pro-efferocytosis mechanisms, and their receptors. Technological advancement has further facilitated lipid mediator metabolipidomic based profiling of healthy and diseased human tissues, highlighting the extraordinary therapeutic potential of SPMs across a broad array of inflammatory diseases including cancer. As current front-line cancer therapies such as surgery, chemotherapy, and radiation may induce various unwanted side effects such as robust pro-inflammatory and pro-tumorigenic host responses, characterizing SPMs and their receptors as novel therapeutic targets may have important implications as a new direction for host-targeted cancer therapy. Here, we discuss the origins of inflammation resolution, key discoveries and the failure of resolution mechanisms in diseases with an emphasis on cancer, and future directions focused on novel therapeutic applications for this exciting and rapidly expanding field.

Inducible Liver Cancer Models in Transgenic Zebrafish to Investigate Cancer Biology

Primary liver cancer is one of the most prevalent and deadly cancers, which incidence continues to increase while treatment response remains poor; thus, in-depth understanding of tumour events is necessary to develop more effective therapies. Animal models for liver cancer are powerful tools to reach this goal. Over the past decade, our laboratory has established multiple oncogene transgenic zebrafish lines that can be robustly induced to develop liver cancer. Histological, transcriptomic and molecular analyses validate the use of these transgenic zebrafish as experimental models for liver cancer. In this review, we provide a comprehensive summary of our findings with these inducible zebrafish liver cancer models in tumour initiation, oncogene addiction, tumour microenvironment, gender disparity, cancer cachexia, drug screening and others. Induced oncogene expression causes a rapid change of the tumour microenvironment such as inflammatory responses, increased vascularisation and rapid hepatic growth. In several models, histologically-proven carcinoma can be induced within one week of chemical inducer administration. Interestingly, the induced liver tumours show the ability to regress when the transgenic oncogene is suppressed by the withdrawal of the chemical inducer. Like human liver cancer, there is a strong bias of liver cancer severity in male zebrafish. After long-term tumour progression, liver cancer-bearing zebrafish also show symptoms of cancer cachexia such as muscle-wasting. In addition, the zebrafish models have been used to screen for anti-metastasis drugs as well as to evaluate environmental toxicants in carcinogenesis. These findings demonstrated that these inducible zebrafish liver cancer models provide rapid and convenient experimental tools for further investigation of fundamental cancer biology, with the potential for the discovery of new therapeutic approaches.

A scoping review on the "burned out" or "burnt out" testicular cancer: When a rare phenomenon deserves more attention

The "burned out" or "burnt out" testicular cancer (BTC) indicates the spontaneous and complete regression of a testicular germ cell tumor in the presence of distant metastases at the diagnosis. As this condition was never reviewed systematically, a scoping review was conducted to scrutinize the available literature on clinical and histological features of BTC patients. Medline was searched from inception to 19 April 2020. A virtual cohort of 68 BTC patients was generated. Our findings highlighted some inconsistencies: BTC was diagnosed in 5,9% of patients not showing distant metastases and in 2,9% of patients who did not undergo an orchiectomy. Besides, evidence of residual tumor was found in 22,7% of testis specimens, recognized as seminoma in 40% of cases. The emerged inconsistencies may derive from the lack of an unequivocal definition of BTC. Larger collaborative studies are needed to define the best diagnostic workup and treatment for BTC patients.

The spontaneous remission of cancer: Current insights and therapeutic significance

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Spontaneous remission (SR) of cancer is a rare but well-documented phenomenon.

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Mechanisms of SR are described in detail.

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Knowing the intricacies of SR would help in devising novel treatment strategies.

Many diseases heal spontaneously. The common cold, for example, remedies itself within a few days in people with an uncompromised immune system. If a disease with a poor prognosis heals in the absence of a targeted therapeutic, many even call it a miracle cure. Such is the case with the spontaneous regression (SR) of malignant neoplasms, a rare but well-documented phenomenon that finds its first mention in the Ebers Papyrus of 1550 BCE. Given the challenges associated with current cancer treatment modalities such as rapidly evolving drug resistance mechanisms, dose-limiting side effects, and a failure to completely eliminate cancer cells, knowledge of how a tumour heals itself would be immensely helpful in developing more effective therapeutic modalities. Although the intricate mechanisms of SR have yet to be fully elucidated, it has been shown that infection-mediated immune system activation, biopsy procedures, and disruptions of the tumour microenvironment play pivotal roles in the self-healing of many tumours. Bacterial and viral infections are especially well-documented in instances of SR. Insights from these findings are paving the way for novel therapeutic strategies. Inspired by bacteria-mediated SR, Bacillus Calmette-Guérin (BCG) has been used as an approved treatment option for non-muscle-invasive bladder cancer (NMIBC). Similarly, Talimogene laherparepvec (T-VEC), the first engineered oncolytic herpes simplex virus (HSV), has been approved by the United States Food and Drug Administration for the treatment of some forms of advanced melanoma. Here we describe the current understanding of SR, explore its therapeutic significance, and offer perspectives on its future.

In situ vaccination with nanoparticles for cancer immunotherapy: understanding the immunology

FDA approval of anti-CTLA4 in 2011 for melanoma immunotherapy was paradigm shifting and dramatically accelerated cancer immunotherapy research. The investment and effort have been exceptionally large, with a commensurate impressive pace of discovery. Historical and current research has validated the following key points: tumors are recognized by the immune system; tumors develop an immunosuppressive environment which suppresses the antitumor immune response; successful immunotherapy must overcome that tumor-mediated immunosuppression. While cancer immunotherapy research expanded, a parallel effort developing nanoparticles (NP) for cancer diagnosis and therapy also received major investment and expanded. Initially the two efforts appeared to have minimal synergy. Systemically administered nanoparticles are rapidly ingested by phagocytic leukocytes, and therefore nanotechnologists developed strategies to avoid NP ingestion by leukocytes in order to accomplish nanoparticle accumulation in tumors rather than liver and spleen. Recently, nanotechnology and cancer immunotherapy have increasingly merged since phagocytic leukocytes are the key to reversing the local tumor immunosuppression and the tendency of NP to be phagocytosed can be exploited to manipulate phagocytes for immunotherapy. This review focuses on in situ vaccination (ISV), an immunotherapy approach that can utilize direct injection of immunostimulatory reagents, including NPs, into tumors to disrupt the local immunosuppression, stimulate effective immune response against the treated tumor, and most importantly, generate a systemic antitumor immune response to eliminate metastatic tumors. While there are many specific options for using NP for ISV (reviewed further in this special issue), this review focuses on immunology concepts needed to understand and design successful NP ISV approaches.

A Patient With Regressed Diffuse Large B-Cell Lymphoma and Aggressive Follicular Lymphoma

Diffuse large B‐cell lymphoma (DLBCL) and follicular lymphoma (FL) are the two most aggressive forms of non‐Hodgkin lymphomas (NHLs). Spontaneous remission of DLBCL is a rare phenomenon. Immune system activation has been observed to play a significant role in the regression of untreated disease on some occasions. We present a case of DLBCL in a 75-year-old male patient who has been free of disease for two months without any treatment due to possible immune-related mechanism, but later he presented with FL.

Early-stage Burkitt lymphoma remained in remission 7 years from diagnosis after only one cycle of chemoimmunotherapy

Burkitt lymphoma (BL) is a rare, mature, fast-growing and highly aggressive B-cell neoplasm. It has a high-proliferation rate with distinctive genetic changes in the C-MYC oncogene. Treatment usually requires intense and frequent chemotherapy regimens with central nervous system prophylaxis as the usual regimens used for other non-Hodgkin's lymphoma yield poor survival in BL. This report discusses a patient who was diagnosed with a stage II, high-grade BL who received one cycle of intense chemotherapy and refused further treatment. That patient remained in complete remission in his last follow-up; 7 years from diagnosis without requiring other therapies for his lymphoma.

Case Report: Spontaneous Remission of an Infraorbital Follicular B-Cell Lymphoma: Case Report and Review of the Literature

Non-Hodgkin lymphomas comprise a heterogeneous group of malignancies, with a wide scope of clinical, radiological and histological presentations. In this paper, a case is presented of a 59-year-old white male with an infraorbital follicular B-cell lymphoma, which appeared as a painless mass in the left cheek. The lymphoma achieved spontaneous remission five and a half months after his diagnostic incision biopsy. The literature is reviewed, focusing on this rare site of presentation and spontaneous remission. In literature, only four cases have been reported with a follicular B-cell lymphoma of the cheek or infraorbital region, and only 26 cases of spontaneous remission of an extracranial non-Hodgkin lymphoma in the head and neck region have been described. To the authors’ best knowledge, this is the first time spontaneous remission of an infraorbital follicular lymphoma could be observed. The nature of the processes inducing spontaneous remission remains obscure. It is important to recognize this phenomenon as this might prevent unnecessary treatment.

Effects of infections on the pathogenesis of cancer

Several studies have shown an inverse relationship between acute infections and cancer development. On the other hand, there is a growing evidence that chronic infections may contribute significantly to the carcinogenesis. Factors responsible for increased susceptibility to infections may include modifications of normal defence mechanisms or impairment of host immunity due to altered immune function, genetic polymorphisms, ageing and malnourishment. Studies have demonstrated that children exposed to febrile infectious diseases show a subsequent reduced risk for ovarian cancer, melanoma and many other cancers, while common acute infections in adults are associated with reduced risks for melanoma, glioma, meningioma and multiple cancers. Chronic inflammation associated with certain infectious diseases has been suggested as a cause for the development of tumours. Mechanisms of carcinogenesis due to infections include cell proliferation and DNA replication by mitogen-activated protein kinase pathway, production of toxins that affect the cell cycle and lead to abnormal cell growth and inhibition of apoptosis. This review was aimed to summarize the available evidence on acute infections as a means of cancer prevention and on the role of chronic infections in the development and progression of cancer.

Combining oncolytic virus with FDA approved pharmacological agents for cancer therapy

INTRODUCTION

Oncolytic viruses (OVs) have been engineered to selectively replicate in cancer cells. While initially thought to exert its anti-cancer effects through direct cytolysis, it is increasingly appreciated that OVs interact with a multitude of cellular processes during its life cycle; FDA approved pharmacologic agents that modulate these cellular processes have been shown to augment the anti-neoplastic effects of OVs. Moreover, because of the release of tumor antigens as well as the innate immuno-stimulatory nature of viruses, OVs induce potent immune responses that augment the anti-tumor effects of FDA approved immunotherapies. There is mounting interest in OV as a platform for combinational anti-cancer therapy in this context.

AREAS COVERED

We will review pre-clinical and clinical data that demonstrate proof-of-principle and potential efficacy for OV-based combination therapies with FDA approved anti-cancer agents.

EXPERT OPINION

While the cytolytic activity of OV remains a key driver for its anti-neoplastic effects, understanding the virus-host interactions may afford opportunities for potential synergism with FDA approved therapeutics that target these interactions. Most intriguingly, the immune stimulatory effects of OVs renders combination with FDA approved immunotherapies more potent. While there are growing clinical trials employing such combination therapy, meaningful advances in this paradigm will require improved understanding of virus-host interactions.

Pulmonary artery coil embolisation prevented tumour progression in a patient with advanced squamous cell lung carcinoma

Background: Squamous cell lung carcinoma (SqCLC) is a type of non-small-cell lung cancer, accounting for 25-30% of all lung cancer cases with a median advanced stage survival of 8-11 months. Here we present a rare case of long-term survival with metastatic SqCLC following coil embolisation of the right pulmonary artery.Case presentation: The 49-year-old patient was diagnosed with stage IV (cT4N3M1) SqCLC in 2007 due to a biopsy-proven central malignant tumour in the right lung and bilateral mediastinal lymphadenopathy. A magnetic resonance imaging scan also revealed a metastatic lesion in the liver. Soon after the diagnosis, the patient experienced pulmonary haemorrhage, which was managed by obturating the intermediate bronchus and performing coil embolisation of the right pulmonary artery. The patient also received chemotherapy in 2007 and 2009 without radiological changes. At three different time points in years 2010-2019, biopsies of the primary tumour were taken. All showed dense connective tissue with no indication of cancer growth. In 2020, a positron emission tomography scan showed no pathological metabolic activity in the lungs and liver. Currently, the patient remains in a stable clinical condition with a good performance status.Conclusion: The long-term clinical benefit indicates a direct effect of coil embolisation on tumour progression. We suggest that coil embolisation of tumour-feeding arteries could be considered as a potential treatment method for patients with SqCLC.

Oncolytic viruses for cancer immunotherapy

In this review, we discuss the use of oncolytic viruses in cancer immunotherapy treatments in general, with a particular focus on adenoviruses. These serve as a model to elucidate how versatile viruses are, and how they can be used to complement other cancer therapies to gain optimal patient benefits. Historical reports from over a hundred years suggest treatment efficacy and safety with adenovirus and other oncolytic viruses. This is confirmed in more contemporary patient series and multiple clinical trials. Yet, while the first viruses have already been granted approval from several regulatory authorities, room for improvement remains.

As good safety and tolerability have been seen, the oncolytic virus field has now moved on to increase efficacy in a wide array of approaches. Adding different immunomodulatory transgenes to the viruses is one strategy gaining momentum. Immunostimulatory molecules can thus be produced at the tumor with reduced systemic side effects. On the other hand, preclinical work suggests additive or synergistic effects with conventional treatments such as radiotherapy and chemotherapy. In addition, the newly introduced checkpoint inhibitors and other immunomodulatory drugs could make perfect companions to oncolytic viruses. Especially tumors that seem not to be recognized by the immune system can be made immunogenic by oncolytic viruses. Logically, the combination with checkpoint inhibitors is being evaluated in ongoing trials. Another promising avenue is modulating the tumor microenvironment with oncolytic viruses to allow T cell therapies to work in solid tumors.

Oncolytic viruses could be the next remarkable wave in cancer immunotherapy.

Spontaneous Tumor Regression in Tasmanian Devils Associated with RASL11A Activation

Spontaneous tumor regression has been documented in a small proportion of human cancer patients, but the specific mechanisms underlying tumor regression without treatment are not well understood. Tasmanian devils are threatened with extinction from a transmissible cancer due to universal susceptibility and a near 100% case fatality rate. In over 10,000 cases, <20 instances of natural tumor regression have been detected. Previous work in this system has focused on Tasmanian devil genetic variation associated with the regression phenotype. Here, we used comparative and functional genomics to identify tumor genetic variation associated with tumor regression. We show that a single point mutation in the 5' untranslated region of the putative tumor suppressor RASL11A significantly contributes to tumor regression. RASL11A was expressed in regressed tumors but silenced in wild-type, nonregressed tumors, consistent with RASL11A downregulation in human cancers. Induced RASL11A expression significantly reduced tumor cell proliferation in vitro The RAS pathway is frequently altered in human cancers, and RASL11A activation may provide a therapeutic treatment option for Tasmanian devils as well as a general mechanism for tumor inhibition.

Oncolytic bacteria: past, present and future

More than a century ago, independent groups raised the possibility of using bacteria to selectively infect tumours. Such treatment induces an immune reaction that can cause tumour rejection and protect the patient against further recurrences. One of the first holistic approximations to use bacteria in cancer treatment was performed by William Coley, considered the father of immune-therapy, at the end of XIX century. Since then, many groups have used different bacteria to test their antitumour activity in animal models and patients. The basis for this reactivity implies that innate immune responses activated upon bacteria recognition, also react against the tumour. Different publications have addressed several aspects of oncolytic bacteria. In the present review, we will focus on revisiting the historical aspects using bacteria as oncolytic agents and how they led to the current clinical trials. In addition, we address the molecules present in oncolytic bacteria that induce specific toxic effects against the tumors as well as the activation of host immune responses in order to trigger antitumour immunity. Finally, we discuss future perspectives that could be considered in the different fields implicated in the implementation of this kind of therapy in order to improve the current use of bacteria as oncolytic agents.

A stochastic model for cancer metastasis: branching stochastic process with settlement

We introduce a new stochastic model for metastatic growth, which takes the form of a branching stochastic process with settlement. The moving particles are interpreted as clusters of cancer cells, while stationary particles correspond to micro-tumours and metastases. The analysis of expected particle location, their locational variance, the furthest particle distribution and the extinction probability leads to a common type of differential equation, namely, a non-local integro-differential equation with distributed delay. We prove global existence and uniqueness results for this type of equation. The solutions' asymptotic behaviour for long time is characterized by an explicit index, a metastatic reproduction number $R_0$: metastases spread for $R_{0}>1$ and become extinct for $R_{0}<1$. Using metastatic data from mouse experiments, we show the suitability of our framework to model metastatic cancer.

Managing Metastatic Thymoma With Metabolic and Medical Therapy: A Case Report

Thymomas consist of neoplastic thymic cells intermixed with variable numbers of non-neoplastic lymphocytes. Metastatic thymomas are typically managed with non-curative chemotherapy to control tumor-related symptoms; no prolonged survival is expected. Metabolic-based approaches, such as fasting and ketogenic diets, target cancer cell metabolism by creating an increased reliance on ketones while decreasing glucose, glutamine, and growth factor availability, theoretically depriving cancer cells of their metabolic fuels while creating an unfavorable environment for cancer growth, which may be beneficial in metastatic thymoma. We report the case of a 37-year-old woman with myasthenia gravis, diagnosed with an inoperable type AB, stage IVA thymoma, who pursued a metabolic intervention consisting of periodic fasting (7-day, fluid-only fasts every 1–2 months), combined with a modified ketogenic diet on feeding days, for 2 years. Fasting-related adverse effects included cold intolerance, fatigue, and generalized muscle aches, all of which resolved during the second year. She experienced two myasthenia relapses, each associated with profoundly reduced oral intake, marked weight loss, and tumor regression-the first relapse was followed by a 32% decrease in tumor volume over 4 months, the second relapse by a dramatic 96% decrease in tumor volume over 4 months. The second relapse also required prednisone to control the myasthenia symptoms. We hypothesize that 2 years of fasting and ketogenic diet therapy metabolically weakened the neoplastic thymic cell component of the thymoma, “setting the stage” for immune activation and extreme energy restriction to destroy the majority of cancer cells during both relapses, while prednisone-induced apoptosis eradicated the remaining lymphocytic component of the thymoma during the second relapse. This case is unique in that a metabolic-based fasting and ketogenic diet intervention was used as the primary management strategy for a metastatic cancer in the absence of surgery, chemotherapy, or radiotherapy, culminating in a near-complete regression. Nearly 3 years after being diagnosed with inoperable metastatic cancer, our patient shows no signs of disease and leads a full and active life.

Water extract from Euglena gracilis prevents lung carcinoma growth in mice by attenuation of the myeloid-derived cell population

The partially purified water extract from Euglena gracilis (EWE) was evaluated for its antitumor and immunomodulatory effects in cell cultures and in a mouse orthotopic lung carcinoma allograft model. In two-dimensional cell culture, the EWE treatment inhibited cell growth of both murine Lewis lung carcinoma (LLC) and human lung carcinoma cells (A549 and H1299) in a dose- and time-dependent manner. In contrast, the growth of mouse bone marrow cells (BMCs), but not mouse splenocytes (SPLs), was stimulated by the treatment with EWE. In three-dimensional spheroid culture, spheroid growth of LLC cells was significantly attenuated by EWE treatment. In a mouse LLC orthotopic allograft model, pretreatment with EWE (150-200 mg/kg/day, via drinking water) three weeks prior to the LLC cell inoculation, but not post-treatment after LLC cell inoculation, significantly attenuated the growth of LLC tumors in immunocompetent syngeneic mouse lung. This tumor growth attenuation coincided with a significant decrease in the population of myeloid-derived cells, primarily neutrophils. Flow cytometric analysis revealed that the EWE treatment significantly attenuated growth of granulocytic myeloid-derived suppressor cells (gMDSC) in BMCs and that this decrease was due to induction of gMDSC-specific apoptosis and differentiation of monocytic MDSCs (mMDSC) to macrophages. The present study provides evidence that EWE pretreatment inhibits lung carcinoma growth mainly by stimulating host antitumor immunity through attenuation of growth of gMDSCs and decreasing the number of peripheral granulocytes. This study suggests that the partially purified extract derived from Euglena gracilis contains significant bioactive materials that prevent lung carcinoma growth.

Spontaneous Remission in a Patient With Acute Myeloid Leukemia Leading to Undetectable Minimal Residual Disease

Although rare, spontaneous remission (SR) of acute myeloid leukemia (AML) has been reported in the literature, the underlying mechanisms driving remission remain unknown. However, it is most commonly associated with a preceding severe infection. We present a case of a 40-year-old man with no past medical history who presented to our hospital with severe left hip pain and fevers and was found to have AML. Chemotherapy was delayed because the patient required extensive debridement and fasciotomy of his left hip and a prolonged course of antibiotics. After his acute illness had stabilized, a repeat bone marrow biopsy was performed which showed no abnormal myeloid blasts and resolution of his original cytogenetic and molecular abnormalities. At the time of this writing, our patient remains in remission with undetectable minimal residual disease (MRD), now 14 months from his initial diagnosis of AML.

Distinct inactivated bacterial-based immune modulators vary in their therapeutic efficacies for treating disease based on the organ site of pathology

Recent developments in understanding how the functional phenotype of the innate immune system is programmed has led to paradigm-shifting views on immunomodulation. These advances have overturned two long-held dogmas: (1) only adaptive immunity confers immunological memory; and, (2) innate immunity lacks specificity. This work describes the observation that innate immune effector cells appear to be differentially recruited to specific pathological sites when mobilized by distinct inactivated bacterial-based stimuli administered subcutaneously. The studies presented suggest that the immune system, upon detecting the first signs of a potential infection by a specific pathogen, tends to direct its resources to the compartment from which that pathogen is most likely originating. The findings from this work puts forth the novel hypothesis that the immunotherapeutic efficacy of a microbial-based stimulus for innate immune mobilization depends on the correct selection of the microbial species used as the stimulant and its relationship to the organ in which the pathology is present.

Evidence for immortality and autonomy in animal cancer models is often not provided, which causes confusion on key issues of cancer biology

Modern research into carcinogenesis has undergone three phases. Surgeons and pathologists started the first phase roughly 250 years ago, establishing morphological traits of tumors for pathologic diagnosis, and setting immortality and autonomy as indispensable criteria for neoplasms. A century ago, medical doctors, biologists and chemists started to enhance "experimental cancer research" by establishing many animal models of chemical-induced carcinogenesis for studies of cellular mechanisms. In this second phase, the two-hit theory and stepwise carcinogenesis of "initiation-promotion" or "initiation-promotion-progression" were established, with an illustrious finding that outgrowths induced in animals depend on the inducers, and thus are not authentically neoplastic, until late stages. The last 40 years are the third incarnation, molecular biologists have gradually dominated the carcinogenesis research fraternity and have established numerous genetically-modified animal models of carcinogenesis. However, evidence has not been provided for immortality and autonomy of the lesions from most of these models. Probably, many lesions had already been collected from animals for analyses of molecular mechanisms of "cancer" before the lesions became autonomous. We herein review the monumental work of many predecessors to reinforce that evidence for immortality and autonomy is essential for confirming a neoplastic nature. We extrapolate that immortality and autonomy are established early during sporadic human carcinogenesis, unlike the late establishment in most animal models. It is imperative to resume many forerunners' work by determining the genetic bases for initiation, promotion and progression, the genetic bases for immortality and autonomy, and which animal models are, in fact, good for identifying such genetic bases.

The cGAS-STING pathway is a therapeutic target in a preclinical model of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, and the incidence of HCC is increasing. Recently, cancer immunotherapy has emerged as an efficient treatment against some cancers. Here we have used a mouse model of mutagen-induced HCC to explore the therapeutic usefulness of targeting the DNA-activated STING pathway in HCC. STING-deficient mice exhibited unaltered initial development of HCC, but had higher number of large tumors at late stages of disease. In the liver of STING-deficient HCC mice, we observed reduced levels of phospho-STAT1, autophagy, and cleaved caspase3. These responses were activated in the liver by treatment with a cyclic dinucleotide (CDN) STING agonist. Importantly, CDN treatment of mice after HCC development efficiently reduced tumor size. Initiation of CDN treatment at an even later stage of disease to allow HCC detection by MR scanning revealed that the majority of tumors regressed in response to CDN, but new tumors were also detected, which were unresponsive to CDN treatment. Overall, the modulation of the STING pathway affects the development of HCC, and holds promise for a use as a treatment of this disease, most likely in combination with other immunomodulatory treatments such as PD1 inhibitors or with standard of care.

Ovarian cancer: Current status and strategies for improving therapeutic outcomes

Of all the gynecologic tumors, ovarian cancer (OC) is known to be the deadliest. Advanced‐stages of OC are linked with high morbidity and low survival rates despite the immense amount of research in the field. Shortage of promising screening tools for early‐stage detection is one of the major challenges linked with the poor survival rate for patients with OC. In OC, therapeutic management is used with multidisciplinary approaches that includes debulking surgery, chemotherapy, and (rarely) radiotherapy. Recently, there is an increasing interest in using immunomodulation for treating OC. Relapse rates are high in this malignancy and averages around every 2‐years. Further treatments after the relapse are more intense, increasing the toxicity, resistance to chemotherapy drugs, and financial burden to patients with poor quality‐of‐life. A procedure that has been studied to help reduce the morbidity rate involves pre‐sensitizing cancer cells with standard therapy in order to produce optimal results with minimum dosage. Utilizing such an approach, platinum‐based agents are effective due to their increased response to platinum‐based chemotherapy in relapsed cases. These chemo‐drugs also help address the issue of drug resistance. After conducting an extensive search with available literature and the resources for clinical trials, information is precisely documented on current research, biomarkers, options for treatment and clinical trials. Several schemes for enhancing the therapeutic responses for OC are discussed systematically in this review with an attempt in summarizing the recent developments in this exciting field of translational/clinical research.

Spontaneous Regression of Myxofibrosarcoma of the Thigh after Open Biopsy

Spontaneous regression of sarcoma is exceedingly rare. A 62-year-old male presented with myxofibrosarcoma of the thigh which regressed after open biopsy. Treatment strategy for this condition is not well-documented in the literature. In this report, we describe the case of a spontaneously regressed myxofibrosarcoma successfully treated by resection where the extent of the tumor was determined from the initial MRI. This case demonstrates that myxofibrosarcoma has the potential to regress spontaneously, and astute awareness of this phenomenon is necessary for appropriate management of this condition.

Relationship between haematological profile and progression or spontaneous regression of melanoma in the Melanoma-bearing Libechov Minipigs

Haematological parameters, plasma iron concentration, and bodyweight were monitored in Melanoma-bearing Libechov Minipigs (MeLiM) from 5 to 18 weeks old. Animals with melanoma progression (P group) and spontaneous regression (SR group) were compared. The P group showed the lowest median values of red blood cell counts (RBC), haematocrit (HCT), haemoglobin concentration (HGB), and bodyweight, whereas the control white (tumour-free) pigs (C group) revealed the highest mean values of these parameters. The mean values of pigs with SR fell between the P and C groups. In addition, a stable concentration of plasma iron was found in the C group, while iron deficiency that increases with age was observed in the MeLiM groups. These results indicate that MeLiM are affected by cancer-related microcytic hypochromic anaemia. The lowest values of HGB, RBC, and HCT, together with the highest number of platelets (PLT) in the P group correspond to melanoma progression. Higher values of these parameters and lower PLT in the MeLiM pigs with SR reflected health improvement due to the destruction of melanoma cells during spontaneous regression. Monitoring of these haematological parameters can help distinguish MeLiM piglets with progression and spontaneous regression of melanoma in the early stages of postnatal development. The findings of this study correspond to findings in human patients in which cancer-related anaemia, thrombocytosis, and iron deficiency are often diagnosed.

Antigen Targets for the Development of Immunotherapies in Leukemia

Immunotherapeutic approaches, including allogeneic stem cell transplantation and donor lymphocyte infusion, have significantly improved the prognosis of leukemia patients. Further efforts are now focusing on the development of immunotherapies that are able to target leukemic cells more specifically, comprising monoclonal antibodies, chimeric antigen receptor (CAR) T cells, and dendritic cell- or peptide-based vaccination strategies. One main prerequisite for such antigen-specific approaches is the selection of suitable target structures on leukemic cells. In general, the targets for anti-cancer immunotherapies can be divided into two groups: (1) T-cell epitopes relying on the presentation of peptides via human leukocyte antigen (HLA) molecules and (2) surface structures, which are HLA-independently expressed on cancer cells. This review discusses the most promising tumor antigens as well as the underlying discovery and selection strategies for the development of anti-leukemia immunotherapies.

Spontaneous Regression of Ovarian Carcinoma After Septic Peritonitis; A Unique Case Report

Despite advances in therapy, ovarian cancer remains the most lethal gynecological malignancy and prognosis has not substantially improved over the past 3 decades. Immunotherapy is a promising new treatment option. However, the immunosuppressive cancer microenvironment must be overcome for immunotherapy to be successful. Here, we present a unique case of spontaneous regression of ovarian carcinoma after septic peritonitis. A 79-year-old woman was diagnosed with stage IIIc ovarian cancer. The omental cake biopsy was complicated by sepsis. Although the patient recovered, her physical condition did not allow further treatment for her ovarian cancer. After 6 months, spontaneous regression of the tumor was observed during surgery. Analysis of the immune infiltrate in the tissues showed a shift from a pro-tumorigenic to an anti-tumorigenic immune response after sepsis. Strong activation of the immune system during sepsis overruled the immunosuppressive tumor microenvironment and allowed for a potent anti-tumor immune response. More understanding of immunological responses in cases with cancer and septic peritonitis might be crucial to identify potential new targets for immunotherapy.